I. Field of the Invention
The present invention relates generally to hydraulic valve assemblies for use in energy transfer units such as automotive, truck and airplane engines. More particularly, the present invention relates to a valve assembly for an energy transfer unit where the valve assembly is operated by a solenoid, the solenoid controlling a sleeve assembly to selectively allow the entrance and exit of hydraulic fluid to affect the raising or lowering of a valve member into either of a closed or open positon respectively.
II. Description of the Relevant Art
Improvements of valving systems for energy transfer units, such units including compressors, pumps and internal combustion engines, are continually being sought. Proper and efficient valving is critical to the efficient operation of an energy transfer unit in that efficiently operated valves are fully operated with only a minimum of energy requirement.
Several approaches have been taken toward improving the efficiency of energy transfer unit valve assemblies. Such advancements include the rotary-valve engine, the two-port poppet-valve engine, and the reed-valve engine. These modifications, while generally making significant improvements in valving, have only proven valuable to a limited extent because to operate a valve system mechanically, the engineer is generally limited by the number of valves possibly situated per cylinder, the necessary position of the valve for operation by one or two cam shafts, and the complicating factor of trying to operate all of the valves from a cam running in a single plane.
In a partial answer to the requirement for maximum flexibility of construction, various hydraulic valve lifting assemblies have been devised and applied. While these systems have more or less resolved some of the problems related to strictly mechanically-lifted valves, they tend to be complex and are not able to respond quickly to changing engine requirements and conditions. This is so because known hydraulic valve assemblies are still generally restricted by mechanical operation, either directly or indirectly, as they relate to the performance and output of the engine.
Accordingly, the prior approaches directed at solving the problems of providing a valve assembly that can be operated in concert with, yet independent of, the engine to maximize performance and minimize inefficiency have failed to eliminate the inconvenience and any effectiveness of known valve systems.